The archer-ranger does lend itself somewhat to shooting from the back ranks once battle is joined. However, it's most effective when it acts in a scouting role leading up to battle. The ideal scenario is that the ranger & rogue sout ahead, pick an important target in the enemy group, then the rogue SAs it, the ranger designates it Hunter's Quary and hits it with Prime Shot - then they both book as the frontliners attack. The Ranger can then spend some time in the back, laying Hunter's Quary damage on some hapless Controller or Artillery monster, and doing a lot more good than he would plinking minions or soldiers. If he doesn't embrace the scouting role, the ranger's Prime Shot is lost and his Hunter's Quary is wasted on hard-to-hit soldiers and mountain-of-hps brutes when he could be using it on a higher value target.
The problem of the Rogue is a common one. Rogues are good scouts, rogues do get to do nice SA damage when they take the first shot. So it's tempting to be out in front, flanking the enemy front line from behind. But, Rogues should then run for the protection of the party defenders. Flanking is good, flanking when it gets you surrounded by the enemy is /bad/.
The funny thing is, the rogue and ranger in my party are acting similarly. The ranger is a dedicated archer and spends 90% of his time shooting from the back rank (along with the wizard and 'lazer' cleric). However, he does take up scouting duties, and will move around in more open combats to get in the occassional prime shot, then scoot when the enemy comes after him. The rogue is, IC, supposed to be impulsive and foolhardy - and the player is that way OOC - so he gets in tons of trouble. Once he's been sufficiently mauled, we keep him in the middle of the party, as a ranged combatant. But, we have a big party (7 if everyone shows up), so we can afford to have a character or two underperforming a little at times.